Link to issue number:

Fixup of #15379

Summary of the issue:

There are some bugs with downloading multiple add-ons at once:

• when switching tab "downloading" status is lost
• if downloads are cancelled and restarted subsequently some errors occur

Description of user facing changes

When switching tab "downloading" status is no longer lost.
Make cancelling downloads safer

Description of development approach

Minor changes

Testing strategy:

Tested via #15350

Known issues with pull request:

None

Change log entries:

N/A

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• Security precautions taken.